log cycle,对数循环； 一个对数循环,就是把数量减少90%,（所需的时间和温度）,微生物数量从1000减少到100,就是一个对数循环,减少到10,就是两个对数循环.
One log cycle is the time and temperature to reduce the number of the target microorganism by 90%,or the log of 10.For example,if your milk contained 1,000,000 microorganisms one log cycle would reduce them to 100,000.Two log cycles would reduce them to 10,000,three to 1,000,four log cycles to 100,five cycles to 10,and six log cycles to 1.